The HF plugs in the first post are chalice shaped, but since the horns are "Salmon type" and the plugs are designed to work with these (slow opening) horns, they are slightly different from yours.
The (mid range) plugs in the second post are (very) different and more conventionally shaped.
So far I've only seen plots of the bass and low / mid horns (up to 800Hz) and those are horribly flat.
In short, I think you are on the right track with your principle.
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Guys, it is the convex diaphragm that makes all the difference here. It allows for (something like) a spherical wavefront that can be matched to a pure conical waveguide. This would be the best of all worlds situation.
The reason why you don't see this with conventional drivers is that you simply can't reach this goal with a concave dome - the path differences are simply too large for that. At least I haven't seen anybody really making it. So it is the flat wavefront that is being taken as granted. It doesn't have to be that way.
The reason why you don't see this with conventional drivers is that you simply can't reach this goal with a concave dome - the path differences are simply too large for that. At least I haven't seen anybody really making it. So it is the flat wavefront that is being taken as granted. It doesn't have to be that way.
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I'm with you here as well. I am not sure what Art is thinking.
And I do agree that your idea has merit, but here is my prediction:
1) it will likely never be tested because building one presents a lot of complex issues that will make a prototype very expensive.
2) if is not very practical because it requires a fixed waveguide and as the marketplace will tell you, one thing that people never seem to agree on is what is the best horn/waveguide. That means that "interchangeability" will continue to rule the market.
3) in the end it will all make little enough difference that it will simply go away into the woodwork.
It's a nice idea to try from a theoretical point of view, but wide acceptance is highly unlikely.
Or just taking almost any existing one and using it from the other side than usualSo the next step is designing a custom driver with a convex diaphragm
I definitely want to make a pair for me as the result. I don't care for the rest, even less for the marketplace
I'm thinking about SLA 3D printing (stereolithography). It doesn't have to be that expensive.
i thought most compression drivers the "acoustic output" is from the concave side of the diaphragm, no?
but i could be misunderstanding what Mabat is saying.
also why would a fixed waveguide be required because of a phase plug redesign? i thought the concept was to make the drivers output be a flat wavefront so that any number of waveguides could be utilized?
An externally hosted image should be here but it was not working when we last tested it.
but i could be misunderstanding what Mabat is saying.
also why would a fixed waveguide be required because of a phase plug redesign? i thought the concept was to make the drivers output be a flat wavefront so that any number of waveguides could be utilized?
I have these two lying around, free to experiment with - 4" and 1.75" diaphragms. Haven't tried yet to remove the original phase plug on the smaller one. BTW, what would be the consequences of keeping it there?
Attachments
These days, a driver designer should be able to "compose" an initial virtual prototype in one day, probably even within a couple hours. The parameters of nearly all driver parts can be tailored to taste.
However, from the research I've read, the diaphragm is the most complex part.
Haven't you considered writing another book? Maybe more focused on a practical loudspeaker building. I mean, within all your posts here on diyAudio and elsewhere, there's so much valuable information that would fill another hundreds of pages at least. That could become another classic in the field.
Regarding ABEC, I'm a bit frustrated right now as it seems that the field observation can't use the user provided mesh but uses always a simple plane instead that intersects the model rather randomly. Nevertheless, after dividing the whole thing into several subdomains, it calculates in an acceptable time. BTW, this is for 20 kHz on a 100 kHz mesh grid. The phase plug used is the most simple variant I could think of for the start - two slots, placed more or less randomly. Will need to use a still longer waveguide.
Maybe a polar map from somewhere inside the waveguide will be a better presentation.
Maybe a polar map from somewhere inside the waveguide will be a better presentation.
Attachments
SUMMA
A science-based approach to design & construction of controlled coverage loudspeaker systems
A science-based approach to design & construction of controlled coverage loudspeaker systems
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